Liquid fuel combustion apparatus



March 29, 1966 A. E. CLARKE ET'AL LIQUID FUEL COMBUSTION APPARATUS 5Sheets-Sheet 1 Filed July 8, 1964 March 29, 1966 A. E. CLARKE ETAL3,242,674

LIQUID FUEL COMBUSTION APPARATUS Filed July 8, 1964 3 Sheets-Sheet 2March 1966 A. E. CLARKE ETAL 7 LIQUID FUEL COMBUSTION APPARATUS FiledJuly 8, 1964 3 Sheets-Sheet 5 United States Patent 3,242,674 LIQUID FUELCOMBUSTION APPARATUS Albert Edward Clarke, Burnley, and David HenryFielding, Clitheroe, England, assignors to Joseph Lucas (Industries)Limited, Birmingham, England Filed July 8, 1964, Ser. No. 381,027 2Claims. (Cl. Gil-49.65)

This invention relates to liquid fuel combustion apparatus for 'gasturbines, and more particularly to the kind comprising an annular flametube contained within an annular air jacket casing, with the upstreamend of the air jacket being adapted to receive air from a compressor,and the downstream end of the flame tube being arranged to discharge theproducts of combustion to a turbine.

The object of the invention is to provide such apparatus in a convenientform.

According to the invention in apparatus of the kind specified a dilutionzone in the downstream end portion of the flame tube is divided into aplurality of angularly spaced outlet ducts by a plurality of hollowpartitions through which air can flow from the outer annular spacewithin the air jacket to the annular space within the air jacket on theinner side of the flame tube, with the partitions having formed thereinapertures through which dilution air can enter the flame tube in asubstantially circumferential direction relative to the engine as awhole.

An example of the invention is illustrated in the accompanying drawingsin which FIGURE 1 is a view in longitudinal section through part of theapparatus, the section being taken on the line 1-1 of FIGURE 2,

FIGURE 2 is a sectional view taken along the line 22 of FIGURE 1,

FIGURE 3 is a section on the line 3-3 of FIGURE 2 and FIGURE 4 is an endview of FIGURE 1 with parts broken away.

In an example of the invention there is provided an annular air jacketcasing which at its upstream end is adapted to receive air from acompressor and at its downstream end is adapted for connection to aturbine housing. Within the air jacket is an annular flame tube 11 whichis mounted in spaced relationship except at its downstream end where ithas a slidable connection with a flanged part 10 of the air jacket.

The dilution zone at the downstream end portion of the flame tube 11 isdivided into a plurality of equiangularly spaced outlet ducts 12 by aplurality of hollow partitions 13 the interiors of which are incommunication with both inner and outer annular spaces defined withinthe air jacket 10. Each partition comprises a pair of side walls 14which extend substantially radially relative to the axis of the engine,an upstream Wall 15 of arcuate cross-section, which is concave as viewedin longitudinal cross-section of the engine, as in FIGURE 1, and whichis convex as viewed in cross-section in a plane perpendicular to that ofFIGURE 1, and a downstream wall 16 closing the downstream end of thepartition. The combustion zone 17 of the flame tube when viewed in axialcross-section immediately upstream of a partition is of substantiallycircular form. Moreover, the annular space between the inner wall of theair jacket 10 and the flame tube 11 is closed by an annular baffle 18 ata point Ice approximately half-way along the combustion zone 17 of theflame tube.

In the pair of side walls 14 of each partition are formed outwardlydirected dilution air inlets 19 and dilution air is directed from thecompressor by means to be referred to into the outer annular spacewithin the air jacket from whence it can flow through the partitions tothe downstream portion of the inner annular space within the air jacket.On its way some of the dilution air will enter the outlet ducts 12through the dilution air inlets 19 in the side walls in a generallycircumferential direction relative to the engine as a whole.

At the upstream end of the flame tube are a plurality of equi-angularlyspaced liquid fuel burners 20 which are situated respectively at thecenter of an equal number of volute swirlers 21.

The upstream end of the air jacket is blanked off by a wall 22 exceptfor an annular air inlet 23 disposed radially outside the circle onwhich the burner axes are disposed. In the air inlet are disposed aplurality of equiangularly spaced air ducts 24 equal in number to thenumber of swirlers. Air entering the inlet 23 between the ducts 24 isdirected into the outer annular space Within the air jacket to serve assecondary and dilution air.

The secondary air from this annular space enters the flame tube throughinlets 26, and a further inlet 27 after passing through the partitions.The dilution air in addition to flowing through inlets 19 flows throughinlets 28 in the inner and outer walls of the ducts 12.

Air entering each duct 24 is directed radially inwards by vanes 25 andis divided into three streams. One stream is directed to the swirler 21to serve as primary air, and the second stream is directed to an annularspace in the air jacket at the upstream side of the baffle 18 fromwhence it can enter the combustion zone 17 of the flame tube through aplurality of inwardly directed secondary air inlets 29 in the inner Wallof the flame tube. The third stream is directed through small holes in aflare 30 as additional primary air.

By a construction as above described, for a given power, the length ofthe flame tube 11 can be shorter than with normal engines therebyenabling the overall length of the engine to be reduced.

Having thus described our invention what we claim as new and desire tosecure by Letters Patent is:

1. A liquid fuel combustion apparatus for gas turbines, comprising anair jacket casing having upstream and downstream ends with the upstreamend being adapted to receive air from a compressor and the downstreamend for connection to a turbine housing, an annular flame tube mountedwithin the air jacket casing in spaced relationship thereto forproviding an annular space between the outside of the tube and theinside of the air jacket casing, said flame tube having upstream anddownstream end portions with said downstream end portion being providedwith a dilution zone, said dilution zone being constituted by aplurality of equi-angularly spaced hollow partitions dividing saiddownstream end portion between adjacent partitions into outlet ducts,each of said hollow partitions including a pair of side walls, adownstream wall and an upstream wall with air being capable of flowthrough the partitions from the outer annular space within the airjacket casing to the annular space within the air jacket casing on theinner side of the flame tube, each of said upstream walls being concaveas viewed in longitudinal cross-section of the apparatus and convex asviewed in cross-section in a plane perpendicular to the longitudinalaxis of the apparatus, and said partitions having apertures thereinthrough which dilution air can enter the flame tube in a substantiallycircumferential direction relative to the apparatus as an entity.

2. The liquid fuel combustion apparatus as claimed in claim 1 in whichthe side walls of each partition extend approximately radially to theaxis of the apparatus and the area of the flame tube immediatelyupstream of the upstream wall of each partition which constitutes thecombustion zone of the tube is of substantially circular form whenviewed in axial cross-section.

References Cited by the Examiner FOREIGN PATENTS 853,180 11/1960GreatBritain. 953,060 3/1964 Great Britain.

MARK NEWMAN, Primary Examiner.

1. A LIQUID FUEL COMBUSTION APPARATUS FOR GAS TURBINES, COMPRISING ANAIR JACKET CASING HAVING UPSTREAM AND DOWNSTREAM ENDS WITH THE UPSTREAMEND BEING ADAPTED TO RECEIVE AIR FROM A COMPRESSOR AND THE DOWNSTRAM ENDFOR CONNECTION TO A TURBINE HOUSING, AN ANNULAR FLAME TUBE MOUNTEDWITHIN THE AIR JACKET CASING IN SPACED RELATIONSHIP THERETO FORPROVIDING AN ANNULAR SPACE BETWEEN THE OUTSIDE OF THE TUBE AND THEINSIDE OF THE AIR JACKET CASING, SAID FLAME TUBE HAVING UPSTREAM ANDDOWNSTREAM END PORTIONS WITH SAID DOWNSTREAM END PORTION BEING PROVIDEDWITH A DILUTION ZONE, SAID DILUTION ZONE BEING CONSTITUTED BY APLURALITY OF EQUI-ANGULARLY SPACED HOLLOW PARTITIONS DIVIDING SAIDDOWNSTREAM END PORTION BETWEEN ADJACENT PARTITIONS INTO OUTLET DUCTS,EACH OF SAID HOLLOW PARTITIONS INCLUDING A PAIR OF SIDE WALLS, ADOWNSTREAM WALL AND AN UPSTREAM WALL WITH AIR BEING CAPABLE OF FLOWTHROUGH THE PARTITIONS FROM THE OUTER ANNULAR SPACE WITHIN THE AIRJACKET CASING TO THE ANNULAR SPACE WITHIN THE AIR JACKET CASING ON THEINNER SIDE OF THE FLAME TUBE, EACH OF SAID UPSTREAM WALLS BEING CONCAVEAS VIEWED IN LONGITUDINAL CROSS-SECTION OF THE APPARTUS AND CONVEX ASVIEWED IN CROSS-SECTION IN A PLANE PREPENDICULAR TO THE LONGITUDINALAXIS OF THE APPARATUS, AND SAID PARTITIONS HAVING APERTURES THEREINTHROUGH WHICH DILUTION AIR CAN ENTER THE FLAME TUBE IN A SUBSTANTIALLYCIRCUMFERENTIAL DIRECTION RELATIVE TO THE APPARAUTS AS AN ENTITY.